1. Field of Use
The present invention relates to a process for the preparation of pharmaceutical mixtures by continuous weighing of the individual components.
2. Description of the Background
In the pharmaceutical industry, the individual components have to date been weighed batchwise and mixed. Because of the danger of separation in the case of different bulk weights and/or flow properties, the mixed batched must be kept relatively small and transfer operations and long transport distances must be avoided. This process is inconvenient and uneconomical and furthermore does not suit modern, continuous tableting processes which do not employ granulation (which to date has always been carried out batchwise). Examples of such processes are the direct tableting of mixtures of active compound and auxiliaries and the extrusion of pharmaceutical mixtures, for example according to German Applications P 3612212.2 and 3612211.4.
The pharmaceutical industry is prejudiced against continuous metering of components for the preparation of a mixture. In the past, this prejudice was justified since the necessary metering accuracy (.+-.5% of the required value) could only be achieved over relatively long periods (several minutes) but not within short periods (less than 1 minute). To be able to use the conventional tableting machines to produce tablets whose uniformity of composition conforms to the specifications of the pharmacopeias very constant metering of each individual component to the second is necessary.